Track maintenance tool



Sept. 29, 1964 1. A. PAYNE TRACK MAINTENANCE Toor.

Filed Aug. 27, 1965 United States Patent O 3,156,859 TRACK MAINTENANCE 'IGOL .lames A. Payne, Warren, Mich., assignor to the United States of America as represented by the Secretary of the Army Filed Aug. 27, 1963, Ser. No. 305,1109 3 Claims. (Cl. 254-51) This invention relates in general to a novel maintenance tool for endless track vehicles, such as combat tanks, for example. Such tracks consist in many cases of an endless interconnected series of split blocks with removable center guides and double pins of the type disclosed in the patent to 3. Proske 2,687,923 issued August 31, 1954. More specifically, the track for which the present tool is designed consists of blocks with pins extending from the ends, the pins of adjacent blocks being joined by an enclosing end connectors or clips with tightening wedges.

In service, it is frequently necessary to replace a track block without removing the track from the vehicle. The track is ordinarily under tension on the vehicle, and the operation of reuniting the track after it has been severed requires considerable force. Prior art track tools require one tool on each side of the track to pull the track together in a sufficiently parallel manner to permit the end connectors to be applied to the projecting ends of the pins as shown in the patent to l. G. Schaeufele 2,382,447, for example.

The principal object of Athe present invention is to provide a single track connecting tool in place of the two adjusting tools now used to install or disconnect tracks on military tanks and the like.

Another object of the invention is to provide a tool which is hydraulically operated wherein the eiiiciency is far greater than the conventional screw jack tool while making the operation faster and easier.

A preferred embodiment of the invention is disclosed, by way of example, in the following description and in the accompanying drawing in which:

FIG. l is a detailed side elevation of the tool applied to the track for pulling the ends of such track structure together into that position permitting the application of a connector plate thereto.

FlG. 2 is a view in elevation of the left hand end of the tool appearing in FIG. 1, with the center guide link of the track removed.

FIG. 3 is a vertical section on line 3 3 of FIG. l.

The track in this case comprises a pair of similar tread units, having split blocks indicated generally at 10, 10, each block consisting of a pair of parallel spaced, tubular metal pivot bearing sleeves 11, 11, extending transversely of the track proper, and rigidly connected at opposite ends by end bars 12, 12. The pivot sleeves 11, 11 and end bars 12, 12 of each tread unit thus forms a rigid open rectangular frame which is pivotally mounted, as usual, on pivot pins 16, 16 extending through rubber bushings 17, 17 in the pivot sleeves 11, 11. Relatively short yC-shaped connectors 18, 18 are suitably secured at opposite ends thereof, so that connectors join similar pairs of pivot pins of adjacent tread units in short-coupled relationship.

In the illustrative form shown herein, the two tread units liti, 1i) are mounted in side-by-side relation on elongated pairs of pivot pins 16, and said pivot pins are also adapted to be joined to adjacent similar tread units at a point between the adjacent ends of the tread units 1t), 10 by a center guide link (not shown). With the guide link removed, the central portions of pins 16 are accessible for engagement by the track tool of the instant invention.

Prior art track tools used for tracks of the above described well known construction require one tool for each side of the track. Thus, to pull the track together in a ice sufficiently parallel manner as to permit the end connectors to be attached the operator must lirst turn the socket of one tool and then the socket of the other tool step-bystep until the track pins are disposed so that the end connectors may be applied thereto.

The single tool 22 of the instant invention consists of a cylinder 24 in which the tubular piston rod 26 is located. The cylinder 24 is provided with a collar 28, welded to said cylinder, and which is machined with a series of threaded holes 29, whereby the plate may be bolted to the collar 28. The plate 36 cooperates with the cylinder 24 and seals ott the end thereof. The outer side of collar 28 is formed with an upwardly extending hook or jaw 32 of a size and shape adapted to engage the exposed central portion of the pivot pins 16. A bleeder valve 34 communicates with the cylinder chamber 36 to permit any air trapped in the cylinder to escape. The lower end of cylinder 24 is threaded at 38, such that the annular closure member 40 may be screwed therein. The closure member 4G is provided with oil seals to prevent iiuid from escaping, and it will be noted that the member 40 slidably receives piston rod 26 and will serve as a guide during cylinder assembly operation. Thus, it will be observed that the cylinder 24, collar 28, jaw 32 and member 40 will move together as a unit.

The piston rod 26 is provided with a reciprocable piston 42 which engages the walls of cylinder 24. The free end of piston rod 26 extends through and is aixed to a closure cap 44 and receives a coupling 46 threaded into the end thereof.

The coupling fixture 46 is connected by a iexible hose 43 to a pump assembly (not shown) for pumping iiuid therefrom into the bore of piston rod 26 and ultimately into the cylinder 24 to move the piston downwardly therein. The piston supporting structure also includes cylindrical tube 5t), extending parallel to the piston rod 26, which slidably engages the cylinder 24. The tube 50 is welded to the sealing cap 44.

Energy storing means in the form of a helical compression coil spring 52 is carried by assembly 22. The coil spring 52 is positioned in the cylinder chamber 36 with one end of the sprinu engaging the plate 30 and the other end of said spring bearing upon the piston 42. Thus, the spring 52 normally holds the piston away from the plate 30 thereby holding the tool assembly 22 in expanded position.

A second complementary jaw 54 is located at the open end of the tube Sti and extends outwardly therefrom while opening towards the open side of the jaw 32. The jaw 54 is secured to the tube Sil by means of collar 55 welded to the tube Sil.

As seen best in FIG. 3, a longitudinal keyway 56 is formed on the inner side of the tube S0. Key 58 is welded to the outside of the cylinder 24 by means of plugwelds 60 to lit within the keyway 56 and guide the reciprocal movement of cylinder 24 in non-rotatable relation to tube 50.

The operation of reuniting the severed ends of the track after a defective block has been replaced is as follows.

The jaw 32 of the cylinder 24 is iirs't engaged with the exposed pivot pin at the center of the track shoe link. By operation of the pump (not shown), fluid is admitted into cylinder 24, 4the piston vwill force clamp 54 toward jaw 32 until the jaw 54 engages the exposed pivot pin at the other end of the break. By reason of the engagement of the jaws with said pins, the tool is now supported at the center of the track structure and substantially parallel therewith. The pump is further operated and the pressure will force the jaws 32 and 54 of the tool to approach each other. Due to the engagement of the jaws on the middle of the pins 16, the shoes are drawn toward each other until they reach the position where the pins 16 are disposed so that end connectors 18 may be applied thereto. After the end connectors' have been initially 'applied .as above mentioned, they hold the shoes together so that the tool 22 may be removed from the track structure simply -by opening la pressure relief valve on the hand pump to back the jaw 54- away from the jaw 32. The end connector wedges are now driven home into position and bolts applied in the usual manner. Lastly, the track shoe guide (not shown) is installed.

The feasibility of using the one track connector of the instant invention at the center of the track in lieu of the two previously used was tested aud determined to be practical. A Blackhawk Pump P85 was used to pressurize the operating uid. A six foot iiexible hose was c-onnected between the fixture 46 and the pump. The tool had a total travel of 10.87 inches. To accurately control the operating pressure, a pressure gage was inserted between the flexible hose 48 and the xture 46. Tests determined that 1700 p.s.i. of force was' required to connect the track on a M60 medium tank. The track was adjusted to the proper tension and the gage reading showed that 3000 p.s.i. was required to connect the track.

Using the :same procedure, the oil pressure was increased to 4200 p.s.i. gage. It was found that the end connectors 18 could not be installed because the force exerted by the jaws on the middle of the track pins 16 caused the track pins to bend. When the pressure was reduced to approximately 3000 p.s.i., the end connectors could be installed. Consequently, the jaws' on the tool should -be made as wide as possible so as to distribute the load over a greater pin area and thus avoid bending the track pins.

While in describing the invention, I have referred in detail to the form, arrangement and construction of the -parts involved, the same is to be considered only in the illustrative sense and therefore I do not wish to be limited thereto except as may be specifically set forth in the appended claims.

I claim:

1. A jack for removing and replacing endless tracks of the type comprising `a plurality of track pad elements having split blocks provided with removable center guides and double pins wherein the central portion of said pins i are exposed, said jack comprising a cylinder and a concentrically spaced tube whereby said cylinder is reciprocable in said tube, interconnecting guide means between said cylinder and tube to prevent rotation of said cylinder with respect to said tube, a closure member sealing one end of said cylinder and a plate sealing the other end of said cylinder, a piston reciprocable in said cylinder and attached to a rod extending slidably through said closure member, an axial bore Within said piston rod whereby uid may be introduced into the cylinder chamber between said closure member and said piston, said tube having a cap sealing one end of said tube, a helical compression spring positioned in said chamber and engaging said plate and said piston, the free end of said piston rod extending through and xably secured to said cap, means connecting a rst jaw to said cylinder as its plate end and means connecting a complementary jaw to said tube at its open end, said jaws being coplanar with complementary inwardly hooked confronting edges of a size and shape adapted to engage the exposed central portion of pivot pins whereby tiuid under pressure is connected to said axial bore to operate said piston rod and force the jaw on said tube toward the jaw on said cylinder under a continuously applied pressure.

2. The combination of claim 1 wherein said jaw connecting means includes collars concentrically secured around the plate end of said cylinder and the open end of said tube to support said jaws on -said cylinder and tube whereby forces on said jaws are uniformly distributed around said cylinder and tube.

3. The combination of claim 1 wherein said interconnecting guide means includes a keyway formed on the inside of said tube and a key welded on the outside of said cylinder.

References Cited in the tile of this patent UNITED STATES PATENTS 1,710,092 Hitchcock Apr. 23, 1929 2,183,842 Madl Dec. 19, 1939 2,383,061 Johnson Aug. 21, 1945 2,682,102 Stone et al. June 29, 1954 3,016,603 Rutland Jan. 16, 1962 

1. A JACK FOR REMOVING AND REPLACING ENDLESS TRACKS OF THE TYPE COMPRISING A PLURALITY OF TRACK PAD ELEMENTS HAVING SPLIT BLOCKS PROVIDED WITH REMOVABLE CENTER GUIDES AND DOUBLE PINS WHEREIN THE CENTRAL PORTION OF SAID PINS ARE EXPOSED, SAID JACK COMPRISING A CYLINDER AND A CONCENTRICALLY SPACED TUBE WHEREBY SAID CYLINDER IS RECIPROCABLE IN SAID TUBE, INTERCONNECTING GUIDE MEANS BETWEEN SAID CYLINDER AND TUBE TO PREVENT ROTATION OF SAID CYLINDER WITH RESPECT TO SAID TUBE, A CLOSURE MEMBER SEALING ONE END OF SAID CYLINDER AND A PLATE SEALING THE OTHER END OF SAID CYLINDER, A PISTON RECIPROCABLE IN SAID CYLINDER AND ATTACHED TO A ROD EXTENDING SLIDABLY THROUGH SAID CLOSURE MEMBER, AN AXIAL BORE WITHIN SAID PISTON ROD WHEREBY FLUID MAY BE INTRODUCED INTO THE CYLINDER CHAMBER BETWEEN SAID CLOSURE MEMBER AND SAID PISTON, SAID TUBE HAVING A CAP SEALING ONE END OF SAID TUBE, A HELICAL COMPRESSION SPRING POSITIONED IN SAID CHAMBER AND ENGAGING SAID PLATE AND SAID PISTON, THE FREE END OF SAID PISTON ROD EXTENDING THROUGH AND FIXABLY SECURED TO SAID CAP, MEANS CONNECTING A FIRST JAW TO SAID CYLINDER AS ITS PLATE END AND MEANS CONNECTING A COMPLEMENTARY JAW TO SAID TUBE AT ITS OPEN END, SAID JAWS BEING COPLANAR WITH COMPLEMENTARY INWARDLY HOOKED CONFRONTING EDGES OF A SIZE AND SHAPE ADAPTED TO ENGAGE THE EXPOSED CENTRAL PORTION OF PIVOT PINS WHEREBY FLUID UNDER PRESSURE IS CONNECTED TO SAID AXIAL BORE TO OPERATE SAID PISTON ROD AND FORCE THE JAW ON SAID TUBE TOWARD THE JAW ON SAID CYLINDER UNDER A CONTINUOUSLY APPLIED PRESSURE. 